Method and apparatus for releasing wall-stuck pipe



Feb. 22, 1966 c. c. BROWN 3,236,307

METHOD AND APPARATUS FOR RELEASING WALL-STUCK PIPE Filed Jan. 11 1962 5Sheets-Sheet 1 icERo c. mow/v INVENTOR.

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A T TOR/V5 Y5 Feb. 22, 1966 C. C. BROWN METHOD AND APPARATUS FORRELEASING WALL-STUCK PIPE Filed Jan. 11 1962 i s N/ A 2 j 1. %/3o 1ig/MM l 29 Y 5 Sheets-Sheet 2 6/65/90 C. BROWN I N V EN TOR.

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ATTORNEY C. C. BROWN Feb. 22, 1966 METHOD AND APPARATUS FOR RELEASINGWALL-STUCK PIPE 5 Sheets-Sheet 5 Filed Jan. 11

INVENTOR.

ATTORNEYS C. C. BROWN Feb. 22, 1966 METHOD AND APPARATUS FOR RELEASINGWALL-STUCK PIPE 5 Sheets-Sheet 4.

Filed Jan. 11 1962 IC/CEPO CBR INVENTOR.

ATTORNEYS Feb. 22, 1966 c. c. BROWN 3,236,307

METHOD AND APPARATUS FOR RELEASING WALL-STUCK PIPE Filed Jan. 11 1962 5Sheets-Sheet 5 cicsRo c. BROWN INVENTOR.

ATTOR NEYS United States Patent 3,236,307 METHOD AND APPARATUS FORRELEASING WALL-STUCK PIPE Cicero C. Brown, Brown Oil Tools, Inc., R0.Box 19236, Houston, Tex. Filed Jan. 11, 1962, Ser. No. 165,596 13Claims. (Cl. 16643) This invention relates to a method and apparatus forreleasing wall-stuck pipe in a well.

Wall-stuck pipe is the term commonly used in the oil well drillingindustry to describe a condition which is encountered during rotarydrilling in which the differential in pressure between the hydrostatichead of the drilling mud in the well bore and the formation pressure ina permeable or porous formation along the bore hole forces the drillpipe against the face of the formation and holds it tightly inengagement with the face of the formation under the differentialpressure so that the pipe string cannot be released either by rotationor by pulling, or even by conventional jarring in many cases. Thiscondition occurs usually when the drill string, particularly the lowerportion comprising the relatively larger diam eter drill collars, hasbeen held stationary for at least a short time opposite a permeableearth formation. Since the weight of the drilling fluid will normally bemaintained so that the hydrostatic head of the drilling fluid exceedsthe formation pressures in order to prevent blowouts, the conditions forcausing drill pipe to become wallstuck will usually be present and willbecome effective, as indicated, when rotation of the drill string isstopped, particularly while the drill collars are opposite a permeableformation. Ordinarily, when wall sticking does occur in the mannerdescribed, circulation can still be maintained through the drill stringin the normal manner, this being one of the usual indications that thedrill string is wall-stuck, rather than that the sticking might be dueto some other condition in the well, as by cavings about the bit or thelike.

Heretofore, various methods and apparatus have been employed ineffecting release of wall-stuck pipe. One of the more common methods isto back-off the portion of the pipe string above the point at which thepipe is stuck and attach to the end of the released pipe a string oftools, including conventional drill stem test tools. The thus equippedpipe is then run back into the well and connected to the stuck portionof the pipe string. Then by opening the valve in the drill stem tester,while sealing off the well bore above the stuck point, the pressuredifferential will be reduced sufliciently to often result in release ofthe stuck pipe. Neither this method nor any others heretofore employedhave proven entirely successful in all instances.

The present invention, therefore, is directed to an improved method foreffecting release of wall-stuck pipe and to several forms of apparatuswhich may be employed for performing the method in accomplishing therelease.

In accordance with the present invention, the method involves a seriesof stages(a) the interposing of a barrier or seal in the annulus betweenthe drill string and the bore wall to thereby isolate the permeableformation from the hydrostatic head of fluid in the annulus; (b)displacing the heavier mud fluid in either the drill string or theannulus with water to thereby develop differential hydrostatic pressurebetween the two columns; (c) circulating the fluid in a direction tomove the heavier column downwardly until it is moving at considerablevelocity; and (d) suddenly blocking the circulation of the fluid. Thissudden interruption in the movement of the fluid generates a greatdownward jarring force by reason of the inertia of the moving column ofheavy fluid aided by the difference in weight between the two columns offluid.

This force will be transmitted to the stuck portion of the drill stringand will usually be great enough to jar the stuck pipe loose from theface of the formation.

Additional objects of this invention are to provide several embodimentsof apparatus particularly adapted for carrying out the method of thisinvention.

Other and more specific objects and advantages of this invention willbecome more readily apparent from the following detailed descriptionwhen read in conjunction with the accompanying drawing illustrating theprocedural steps of the method and several useful embodiments ofapparatus for practicing the method.

In the drawing:

FIGS. 1, 2 and 3 are generally diagrammatic views showing several stagesin the operation of the method and apparatus in a well bore;

FIGS. 4, 5 and 6 are longitudinal, partly sectional views of one form ofapparatus in accordance with this invention, the parts of the apparatusbeing shown in different operating positions;

FIGS. 7 and 8 are cross-sectional views taken generally along lines 77and 88, respectively, of FIG. 4;

FIG. 9 is a cross-sectional view taken along line 99 of FIG. 1;

FIG. 10 is a view similar to FIG. 4 illustrating another embodiment ofthis invention;

FIG. 11 is a generally diagrammatic view similar to FIG. 2, showing theembodiment of FIG. 10 installed in the drill string; and

FIGS. 12 and 13 are. diagrammatic views generally similar to FIGS. 2 and3, illustrating two stages in the operation of still another apparatusembodiment in ac cordance with this invention.

FIG. 1 is a generally diagrammatic view of a well W having its upperportion lined in the usual manner with a casing C, leaving a lowerunlined portion which intersects a porous or permeable earth formation Eshown as having a number of fissures F which, for purposes ofillustration, are shown in greatly exaggerated scale, the fissuresproviding passages for the fiow of drilling fluid into formation E whenthe hydrostatic pressure of the drilling fluid in the well bore exceedsthe pressure in formation E.

As seen in FIG. 1, the lower portion of a drill string S, comprising thedrill collars D, has been stuck to the wall of formation E bydifferential pressure between the fluid column in the bore hole and thatin the formation E. The usual drill bit B is shown connected in theusual manner to the lower end of the string of drill collars D and fluidcirculation ports P are shown in the bit through which drilling fluidwill normally be discharged from the bit. The drill string S is shown ashaving been disconnected from the stuck portion of the string and is inprocess of being withdrawn from the well. The well head is shownequipped with conventional blowout preventors A, and a valved connectionL is shown communicating with the annulus N between the drill string Sand the wall of casing C. The arrows in FIGS. 1 and 9 indicate thedirection of movement of fluid from the well bore into formation E,which is responsible for forcing the drill collars D against the face ofthe formation. Usually a filter cake will have built up on the face ofthe formation and it is into this cake that the drill collars or otherportions of the pipe string will be embedded under the diiferentialforce exerted by the drilling fluid column. Ordinarly also, the stickingwill occur when the bit is off bottom, as illustrated.

After the drill string has been released from the stuck drill collars,it will be withdrawn from the well and will have connected to its lowerend an apparatus or tool, in accordance with this invention, designatedgenerally by the numeral 20. Thereafter the drill string will be run 3back into the well so that the lower end of the tool may be reconnectedto the drill collars D. This stage is illustrated in FIG 2.

FIGS. 4, 5 and 6 illustrate the details of tool 20. This tool comprisesa tubular body 21 into the lower end of which is threadedly inserted theupper end of a sub 22, the lower end of which carries an externallythreaded pin 23 for threaded reception in a tool joint socket 24provided at the upper end of drill collar D, thereby forming the meansby which the apparatus may be connected to the drill collars. A numberof radial ports 25 are provided through the wall of sub 22 forcommunicating the bore 26 of body 21 with the annulus N. The upper endof sub 22 extends interiorly of bore 26. A tubular mandrel 28 isslidably mounted in bore 26 of the body and projects through its upperend, being provided with an externally threaded pin 29 at its upper endfor connection into a collar 30 by means of which mandrel 28 and theapparatus, as a whole, may be connected to drill string S. The externaldiameter of mandrel 28 is made substantially less than the diameter ofbore 26, providing substantial clearance therebetween. A tubular bushing31 is screwed into the upper end of body 21 and has a bore 32 having asliding fit about the exterior of mandrel 28. Bushing 31 is counterboredfrom its upper end to provide a stufling box 33 containing packing 34for forming a fluid-tight slidable seal about mandrel 28 near the upperend of body 21. Secured to the upper end of bushing 31 and surroundingmandrel 28 is an upwardly opening cup-shaped packer or seal member 35which is adapted to form a fluid-tight seal between the exterior of body21 and the wall of casing C. The upwardly opening form of the cup-shapedseal member serves to seal the annulus against downward movement offluid, while permitting upward flow of fluid through the annulus pastthe seal member. A plurality of radial ports 36 are provided through thewall of mandrel 28 to provide communication between the bore 37 of themandrel and the exterior thereof, the ports 36 being disposedintermediate the ends of the mandrel. The lower end of bushing 31 isprovided with longitudinal slots opening downwardly to form an annularclutch member 38 positioned in the space between mandrel 28 and body 21.A similar but upwardly facing clutch member 39 is formed on the upperend of sub 22. Carried on the exterior of mandrel 28, spaced at shortdistance above the lower end, is a series of angularly spaced,longitudinally extending splines 40 adapted to engage either of theclutch members 38 or 39, depending upon the position of the mandrelrelative to body 20, whereby to clutch the mandrel and the connectedportion of pipe string S to body 21 and thence to drill collars D. Whenthe mandrel is at any position at which the splines are between the twoclutch members, the drill string is free to rotate relative to body 21aand drill collars D. The lower end of mandrel 28 has seated in itsexterior a pair of longitudinally spaced packing elements 41, such asconventional O-rings which are adapted, when the mandrel is in itslowermost position in body 21, to seal between the mandrel and sub 22 atpoints above and below the ports 25, the lower end portion of themandrel thus defining a sleeve valve 42 for opening and closing ports25. Sub 22 is provided with an internal upwardly facing shoulder 43 tolimit downward movement of the mandrel so that when the lower end of themandrel has engaged shoulder 43, seals 41 will be positioned above andbelow ports 25, closing off the latter.

FIG. 5 illustrates a position in which the mandrel 28 has been elevatedjust enough to raise the sleeve valve 42 above :ports 25, therebyopening communication between the bore of the pipe string and theannulus.

FIG. 6 illustrates still another position of the apparatus in which themandrel has been elevated to its maximum extent, wherein splines 40 areengaged in upper clutch member 38 at which position ports 36 will beelevated above seal member 35, placing the bore of the pipe string incommunication with annulus N at a point above seal member 35.

By providing the relatively movable connection between mandrel 28 andbody 21, it is possible to circulate drilling or wash fluid at severalpoints relative to the stuck portion. When the bit is clear, circulationcan be carried through the bit ports P in the usual manner, mandrel 28being in its fully retracted position closing ports 25 (FIG. 4). If thebit ports are plugged by cavings or the like, mandrel 28 may be elevatedsufliciently to move sleeve valve 42 to a point opening ports 25 (FIG.5), whereupon circulation may be established at a point above the bit.Finally, the mandrel may be pulled up to its fully extended position atwhich ports 36 will be positioned above seal member 35 aand circulationestablished above the top of the drill collars.

In operation, the tool will be positioned to establish circulation atany of the one of three points as determined by the position of themandrel, as previously described, and water will be pumped into drillstring S through a suitable connection K at its upper end (FIG. 2) todisplace the heavy mud fluid from the interior of the drill string intoannulus N. As indicated by the arrows in FIG. 2, circulation in thisexample has been established through the bit ports P, the mandrel beingin its fully retracted position as illustrated in FIG. 4. Only enoughdisplacement of the heavy mud by water is effected to leave the drillstring filled with water while retaining the heavier mud fluid in theannulus. The resulting difference in weight of the two fluid columnswill exert a sub stantial downward force on seal member 35 and therebyupon body 21 and drill collars D. As indicated previously, the form ofseal member 35 is such that upward flow of fluid in the annulus past theseal will occur but reverse flow cannot occur, the weight of the fluidcolumn in annulus N being etfective to urge the seal member into sealingengagement with the wall of casing C.

When the displacement of the heavy drilling fluid from drill string Shas been completed, the stning is elevated sufficiently to raise mandrelports 36 above seal member 35, as seen in FIG. 3. Thereupon circulationis reversed, that is, the heavier drilling fluid will be pumped throughvalved connection L into annulus N and thence through ports 36 intodrill string S and upwardly to the top of the well and out of connectionK. This reverse circulation is continued until the column of fluid inthe annulus is moving downwardly at a relatively high velocity. As soonas a suitable velocity has been attained, drill string S will be loweredto move ports 36 into the bore of body 21 below seal member 35 andpacking 34. This movement, which is performed quickly, serves tosuddenly and sharply interrupt or block the rapidly moving column offluid. The resulting inertia of the moving column of heavy fluid, aidedby the difference in weight between the heavier fluid in the annulus andthe column of water in the drill string, produces a sudden tremendousdownwardly directed jarring force on seal member 35 and thence on body21 and the drill collars attached thereto. The tremendous jarring forcethus applied will jar the drill collars loose from the wall of formationE. This action is also assisted by the isolation of the heavy column offluid in the annulus from earth formation E by seal member 35, therebytending to reduce the difierential pressure responsible for the stickingof the drill pipe.

By repeating the previously described sequence of operations, repeatedjarring blows may be struck on the stuck pipe should the first blow beineffective to release the stuck pipe. The magnitude of the jarringforce will depend upon the velocity of the downwardly moving column andthe diiference in the specific gravities of the two columns of fluid.Upon release of the drill collars, the entire pipe string will bewithdrawn from the well, and apparatus 20 removed from the pipe stringso that the latter may be re-constituted in its original form forcontinuing drilling.

As illustrated and described previously, the seal member is shownpositioned inside casing C and where it is possible to locate the sealmember in a metallic casing, the seal member may be of the simplecup-shaped form illustrated. However, since the point at which stickingoccurs may be a long distance below any casing, thereby requiring theseating of the seal in an open hole, since the seal should be as nearthe stuck point as practicable, a modified form of seal member may beemployed, as illustrated in FIGS. and 11.

In this modification, all of the structure of tool is identical withthat previously described, except for the shape of seal member 35. Inthis modification, the seal member comprises a tubular sleeve aconstructed of flexible resilient material and having its lower endconnected to bushing 31 in the same manner as in the previouslydescribed embodiment. The upper end of sleeve member 35a, instead ofbeing free to flex radially, as in the case of the lip on seal member35, is secured to a metal ring having an inwardly turned flange 46 whichslidably engages the exterior of mandrel 28. A plurality of ports 47extend through the wall of ring 45 providing communication between theinterior of sleeve 35a and annulus N.

With this embodiment, when the tool is operated in an unlined portion ofthe bore hole, the fluid in the annulus will flow through ports 47 intothe interior of sleeve member 35a and hydrostatic pressure exerted bythis fluid on the inside of sleeve member 35:: will expand the latterinto tight sealing engagement with the wall of the well bore. Theflexible character of the sleeve member will permit it to accommodateitself to the irregularities which are normally present in the wall ofthe unlined bore.

The operation of this modification is identical of that previouslydescribed since the for-m of the seal member represents the onlydiiference in the construction of the device, FIG. 11 showing the deviceas positioned in the drill string during operation.

FIGS. 12 and 13 illustrate still another embodiment of the apparatus bymeans of which the jarring force may be generated and applied. In thisembodiment, a tubular nipple 50 is interposed between drill string S andthe upper end of tool 20, the nipple being provided internally with anannular plug seat 51 for the reception of a plug 52 which may be droppedor pumped through drill string S.

In this embodiment circulation of fluid will be conducted with themandrel in the appropriate position :as may be required to establishcirculation in the manner previously described. Thereafter, the mandrelwill be lifted to the position in FIG. 6 at which the ports 36 will beabove seal member 35. This position is illustrated also in FIG. 12.Water will now be pumped through connection L into the annulus andthence through ports 36 into and up the interior of drill string S, thatis, reverse circulation will be conducted to displace the heavier fluidfrom the annulus into the interior of the drill string, the column ofheavy fluid being retained in the drill string. The pump is thenconnected to the top of the drill string through connection K and fluidpumped into the drill string to start the column therein movingdownwardly until it attains a suflicient velocity. As this pumping isunderway, plug 52 will be dropped into the drill string and pumped downwith the fluid. When the plug lands on seat 51 (FIG. 13) the movement ofthe entire column of fluid in the drill string will be abruptly stoppedand the inertia in this column, aided by the difference in weightbetween the internal and external columns of fluid, will generate andapply a heavy downward jarring force through mandrel 28 to the drillcollars to jar them loose, as previously described.

As will be evident from the foregoing, the primary feature of thisinvention is the procedure by which the inertia of the moving column offluid may be employed as a jarring mechanism by which wall-stuck pipemay be 6 released. This jarring action is made more effective by twoadditional features: (1) making the specific gravi-ties of the twocolumns of fluid in the drill string and the annulus diflFerent; and (2)interposing a fluid-tight barrier between the formation responsible forthe sticking and the column of fluid in the annulus which creates thepressure differential producing the sticking of the drill pipe.

It will be understood that various changes and modifications may be madein the illustrative embodiments of the method and apparatus hereindescribed within the scope of the appended claims, but without departingfrom the spirit of this invention.

What I claim and desire to secure by Letters Patent is:

I. The method of releasing Wall-stuck pipe in a Well, comprising,removing the free portion of the pipe, placing means in the well bore toform and seal ofi an annulus therein above the stuck point, connectingsaid seal-forming means to the wall-stuck portion of the pipe,establishing circulation of a fluid between the interior of the stuckpipe and the well annulus above the stuck point to thereby establishseparate upwardly and downwardly moving columns of said fluid, andabruptly interrupting the movement of the downwardly moving column offluid whereby to generate a high energy downward jar directed againstsaid pipe to release the same.

2. The method of releasing wall-stuck pipe in a well, comprising,removing the tree portion of the pipe, placing means in the well bore toform and seal off an annulus above the stuck point and connecting thesame to the stuck portion of the pipe string, establishing circulationof a hydraulic fluid between the interior of the stuck pipe and the wellannulus to thereby establish separate upwardly and downwardly movingcolumns of said fluid, above the seal-forming means, introducing intoone of said columns a hydraulic fluid of lower specific gravity that theoriginal fluid to displace the latter from said one of said columns tothe other, thereupon reversing the direction of flow between the wellannulus and the interior of the pipe and causing the higher specificgravity column to flow downwardly at high velocity, and abruptlyinterrupting the movement of the downwardly moving column of fluidwhereby to generate a high energy downward jar against said pipe torelease the same.

3. The method according to claim 2 wherein said lower specific gravityfluid is introduced into the column in the interior of the pipe.

4. The method according to claim 2 wherein said lower specific gravityfluid is introduced into the column in said annulus.

5. Apparatus for use in releasing wall-stuck pipe in a well, comprising,relatively movable inner and outer tubular members forming a telescopicconnection means, means carried by the outer connection member forconnection to the wall-stuck portion of a pipe string, means carried bythe inner connection member for attachment to the lower end of the freeportion of the pipe string, be tween the adjacent ends of the wall-stuckportion of a pipe string and the free portion thereof, seal meanscarried by the outer member of said connection means for sealing oil theannulus between the stuck portion of the pipe string and the well wallabove the stuck point, passage means in said connection means providingfluid communication between the interior of the pipe string and theannulus, and closure means operably associated with the pipe string forclosing said passage means.

6. Apparatus according to claim 5 wherein said seal means comprises anupwardly opening flexible cup seal.

7. Apparatus according to claim 5 wherein said passage means comprisesports in the wall of said inner tubular member movable therewith betweenpositions above and below said seal means by longitudinal movement ofthe inner member relative to the outer member.

8. Apparatus according to claim 5 wherein said lastmentioned meanscomprises a plugging element insertable through the bore of said pipestring and a seat in the bore of said inner tubular member to receivesaid plugging element to close the bore of said inner tubular member.

9. Apparatus for use in releasing wall-stuck pipe in a well, comprising,relatively movable inner and outer tubular members forming a telescopicconnection means, means carried by the outer connection member forconnection to the wall-stuck portion of a pipe string, means carried bythe inner connection member for attachment to the lower end of the freeportion of the pipe string, between the adjacent ends of the wall-stuckportion of a pipe string and the free portion thereof, cooperatingclutch elements positioned on the respective members for releasablysecuring said members against relative rotation, seal means carried bythe outer member of said connection means for sealing ofi the annulusbetween the stuck portion of the pipe string and the well wall above thestuck point, passage means in said connection means providing fluidcommunication between the interior of the pipe string and the annulus,and closure means operably associated with the pipe string for closingsaid passage means.

19. Apparatus for use in releasing wall-stuck pipe in a well,comprising, relatively movable inner and outer tubular members forming atelescopic connection means, means carried by the outer connectionmember for connection to the wall-stuck portion of a pipe string, meanscarried by the inner connection member for attachment to the lower endof the free portion of the pipe string, between the adjacent ends of thewall-stuck portion of a pipe string and the free portion thereof,cooperating clutch elements positioned on the respective tubular membersfor releasably securing said members against relative rotation, internalseal means mounted in the upper end portion of the outer tubular memberto form a slidable seal between said tubular members, external sealmeans mounted on the outer tubular member for sealing off the annulusbetween the stuck portion of the pipe string and the well wall above thestuck point against downward flow of fluid through the annulus, passagemeans in said connection means providing fluid communication between theinterior of the pipe string and the annulus, and closure means operablyassociated with the pipe string for closing said passage means.

11. Apparatus according to claim 10 wherein said external seal meanscomprises an upwardly opening flexible cup seal.

12. Apparatus according to claim 10 whereinsaid passage means comprisesports in the wall of said inner tubular member movable therewith betweenpositions above and below said internal seal means by longitudinalmovement of the inner member relative to the outer member.

13. Apparatus for use in releasing wall-stuck pipe in a well,comprising, relatively movable inner and outer tubular members forming atelescopic connection means between the adjacent ends of the wall-stuckportion of a pipe string and the free portion thereof, internal sealmeans mounted in the upper end portion of the outer tubular member toform a slidable seal between said tubular members, external seal meansmounted on the outer tubular member for sealing off the well annulusabove the stuck point against downward flow of fluid through theannulus, first passage means in the outer tubular member below theexternal seal means providing fluid communication between the interiorand exterior of the outer tubular member, valve means positioned on theinner tubular member for movement between positions opening and closingsaid first passage means in response to relative longitudinal movementbetween said tubular members, second passage means through the wall ofthe inner tubular member above said valve means, said second .passagemeans being movable with said inner tubular member between positionsabove and below said internal seal means by said longitudinal movementof the inner tubular member relative to the outer tubular member.

References Cited by the Examiner UNITED STATES PATENTS 249,228 11/1881Dower 166-184 2,674,315 4/1954 Brown 166l321 X 2,753,940 7/1956 Bonner.2,808,887 10/1957 Erwin 166-117 X 2,963,092 12/1960 Anderson et al.166-492 X CHARLES E. OCONNELL, Primary Examiner.

1. THE METHOD OF RELEASING WALL-STUCK PIPE IN A WELL, COMPRISING,REMOVING THE FREE PORTION OF THE PIPE, PLACING MEANS IN THE WELL BORE TOFORM AND SEAL OFF AN ANNULUS THEREIN ABOVE THE STUCK POINT, CONNECTINGSAID SEAL-FORMING MEANS TO THE WALL-STUCK PORTION OF THE PIPE,ESTABLISHING CIRCULATION OF A FLUID BETWEEN THE INTERIOR OF THE STUCKPIPE AND THE WELL ANNULUS ABOVE THE STUCK POINT TO THEREBY ESTABLISHSEPARATE UPWARDLY AND DOWNWARDLY MOVING COLUMNS OF SAID FLUID, ANDABRUPTLY INTERRUPTING THE MOVEMENT OF THE DOWNWARDLY MOVING COLUMN OFFLUID WHEREBY TO GENERATE A HIGH ENERGY DOWNWARD JAR DIRECTED AGAINSTSAID PIPE TO RELEASE THE SAME.